The three-dimensional cytoarchitecture of developing murine muscle spindles

1981 ◽  
Vol 87 (1) ◽  
pp. 133-147 ◽  
Author(s):  
Kenneth Kozeka ◽  
Marcia Ontell
Keyword(s):  
Three Dimensional ◽  
Muscle Spindles

Predicting Any Arm Movement Feedback to Induce Three-Dimensional Illusory Movements in Humans

2010 ◽  
Vol 104 (2) ◽  
pp. 949-959 ◽  
Author(s):  
Chloé Thyrion ◽  
Jean-Pierre Roll
Keyword(s):  
Three Dimensional ◽  
Arm Movements ◽  
Arm Movement ◽  
Muscle Spindles ◽  
Proprioceptive Information ◽  
Human Arm ◽  
Muscle Groups ◽  
Coding Rules ◽  
Straight Lines ◽  
2D And 3D

Our sense of body posture and movement is mainly mediated by densely packed populations of tiny mechanoreceptors present in the muscles. Signals triggered in muscle spindles by our own actions contribute crucially to our consciousness of positions and movements by continuously feeding and updating dynamic sensorimotor maps. Deciphering the coding rules whereby the nervous system integrates this proprioceptive information perceptually could help to elucidate the mechanisms underlying kinesthesia. The aim of the present study was to test the validity of a “propriomimetic method” of predicting the proprioceptive streams emitted by each of the muscles involved in two- (2D) and three-dimensional (3D) arm movements. This method was based on the functional properties of muscle spindle populations previously recorded microneurographically in behaving humans. Ia afferent patterns mimicking those evoked when the “arm–forearm” ensemble is drawing straight lines, graphic symbols, and complex 3D figures were calculated. These simulated patterns were then delivered to the main elbow and shoulder muscle tendons of motionless volunteers via a set of vibrators. Results show that the simulated proprioceptive patterns applied induced, in passive subjects, illusory 2D and 3D arm movements, the trajectories of which were very similar to the expected ones. These simulated patterns can therefore be said to be a substitute for the Ia proprioceptive feedback evoked by any human arm movement and this method can certainly be extended to other musculoskeletal ensembles. The illusory movements induced when these proprioceptive patterns are applied to muscle groups via sets of vibrators may provide useful tools for sensorimotor rehabilitation purposes.

scholarly journals Three-Dimensional Assessment of Upper Limb Proprioception via a Wearable Exoskeleton

2021 ◽  
Vol 11 (6) ◽  
pp. 2615
Author(s):  
Elisa Galofaro ◽  
Erika D’Antonio ◽  
Fabrizio Patané ◽  
Maura Casadio ◽  
Lorenzo Masia
Keyword(s):  
Neurological Diseases ◽  
Scientific Evidence ◽  
Three Dimensional ◽  
Sensory Information ◽  
Elbow Flexion ◽  
Muscle Spindles ◽  
Shoulder Abduction ◽  
Anatomical Location ◽  
Preferred Direction ◽  
Flexion Extension

Proprioception—the sense of body segment’s position and movement—plays a crucial role in human motor control, integrating the sensory information necessary for the correct execution of daily life activities. Despite scientific evidence recognizes that several neurological diseases hamper proprioceptive encoding with consequent inability to correctly perform movements, proprioceptive assessment in clinical settings is still limited to standard scales. Literature on physiology of upper limb’s proprioception is mainly focused on experimental approaches involving planar setups, while the present work provides a novel paradigm for assessing proprioception during single—and multi-joint matching tasks in a three-dimensional workspace. To such extent, a six-degrees of freedom exoskeleton, ALEx-RS (Arm Light Exoskeleton Rehab Station), was used to evaluate 18 healthy subjects’ abilities in matching proprioceptive targets during combined single and multi-joint arm’s movements: shoulder abduction/adduction, shoulder flexion/extension, and elbow flexion/extension. Results provided evidence that proprioceptive abilities depend on the number of joints simultaneously involved in the task and on their anatomical location, since muscle spindles work along their preferred direction, modulating the streaming of sensory information accordingly. These findings suggest solutions for clinical sensorimotor evaluation after neurological disease, where assessing proprioceptive deficits can improve the recovery path and complement the rehabilitation outcomes.

Prenatal Development of Muscle Spindles in the Mouse

1981 ◽  
Vol 39 ◽  
pp. 510-511
Author(s):  
Kenneth Kozeka
Keyword(s):  
Three Dimensional ◽  
Muscle Spindles ◽  
Prenatal Development ◽  
In Utero ◽  
Peripheral Region ◽  
Electron Microscopic ◽  
Afferent Nerves ◽  
Fusimotor Innervation ◽  
Spindle Development ◽  
Peripheral Regions

A closely spaced, serial, light and electron microscopic technique has permitted determination of the patterns of distribution, three dimensional cytoarchitecture and ultrastructural characteristics of developing muscle spindles in the fetal mouse extensor digitorum longus muscle (Figs. 1-6).Spindle development begins at 15 days in utero, when unmyelinated afferent nerves contact large, primary myotubes, located at the muscle's neurovascular hilum. By 17 days in utero the adult number of spindles containing one or two myotubes, can be identified in serial ultrathin sections through the myotube's sensory innervated region. While the primitive capsule of the spindle surrounds the intrafusal myotubes, it is initially confined to the sensory area and does not extend the length of the myotube. At this stage the peripheral regions of the intrafusal myotubes are morphologically indistinguishable from neighboring extrafusal myotubes.It is in this peripheral region that fusimotor innervation will develop.By following the spindles in serial, spaced (i.e., 15μm intervals), ultrathin transverse sections along their length, it is possible to establish the continuity of the sensory innervated region with the peripheral regions of the intrafusal myotube and to determine that fusimotor innervation is not present at 17 days in utero.

The orbit of Pluto over a long interval of time

1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer
Keyword(s):  
Periodic Orbit ◽  
Numerical Integration ◽  
Restricted Problem ◽  
Three Dimensional ◽  
The Third ◽  
Circular Restricted Problem ◽  
Resonance Relation

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Sign in / Sign up

Export Citation Format

Share Document